IEC 60050-721 Amd.4 Ed. 1.0 b:2019

IEC 60050-721 Amd.4 Ed. 1.0 b:2019 Amendment 4 - International Electrotechnical Vocabulary (IEV) - Part 721: Telegraphy, facsimile and data communication

Amendment by International Electrotechnical Commission, 10/17/2019